1. Field of the Invention
The invention relates to electronic power inverters for providing an alternating current source of electrical energy from a direct current source of electrical energy, and refers more specifically to an active snubber structure and method for use in conjunction with an electronic power inverter including electronic switches for limiting turn off losses in the electronic switches during operation of the inverter.
2. Description of the Prior Art
In the past, converting a direct current voltage into an alternating current voltage was accomplished by using a direct current motor to drive an alternating current generator at the correct speed to generate a desired voltage and frequency of alternating current electrical energy.
Electronic devices commonly called power inverters have been developed to accomplish the same function. Power inverters utilize a number of different electronic circuits.
Electronic power inverters have in common the use of electronic switches for switching the direct current energy supplied to a load on and off and for changing the polarity of the electrical energy applied across the load. The electronic switches utilized have inherent turn on and turn off energy losses due to their acting as variable resistors during turn on and turn off. The turn off time for the electronic switches utilized in power inverters is normally much larger than the turn on time so that most energy loss during switching of the electronic switches is during turn off time.
Accordingly, snubber circuits have been utilized in the past in conjunction with electronic power inverters for reducing switching losses during turn off of electronic switches in the power inverters. Such snubbing circuits as have been utilized in the past have been complicated, and therefore expensive to produce, and have potential for malfunction due to their complexity.